Safety pulley construction



Jan. 6, 1931. c. nuauqu:

SAFETY PULLEY CONSTRUCTION 2 Sheets-Shoot 1 Filed 001:. 22, 1928 1931. c. DUBUQUE 1,787,516

SAFETY PULLEY CONSTRUCTION Filed Oct. 22, 1928 2 Sheets-Shunt 2 Invennr Patented Jan. 6, 1931 I UNITED PA E T orricn CHARLES DUBUQUE, on' innsnvorrv, NEW messy, A ssren on' fro Dewe -E SAFETY I PULLEY 0011?.

' SAFETY run- 1 oons rauorron'.

hpplication fi led October 22,1928. Serial No. 31 1,1 14.

The present invention relates to improve ments in pulleys and has for its primary ob je 3t to. provide means for automatically and positively gripping the rope or cable that is trained over the sheave of therp'ulley in case'the cable accidentally breaks, thus preventing any serious injury being sustained by the workman occupying the platform that is suspended by the cable. 1

0 j .A further objectis to provide a pulley of the above mentioned characterwhich'includes a vertically movable sheave that is arranged in the pulley block, resilient means'being associated with the supporting V means-for 5 the sheave for normally urging the same upwardly, the cable that is trained over the sheave being caused to" exert a downward pressure on the sheave to tension thevsprings when the ends of the'cable are attached to a 0 platform that is to'be suspended by the pulley blocks, said pulley block being formed with means at the top thereof for biting engagement with-the cables in case the cable breaks, said spring means automatically moving the sheave upwardly todispose the tooth in an operative position.

A further object is to provide a pulley of r the above mentioned character which:.sis

Simple in construction, inexpensive, strong 0 and durable and further well adapted to the purpose for which it isd'esigned.

Otherobjects and advantages of the invention will become apparent from the fol-' lowing description when taken in connection with the accompanying drawing.

In the accompanying drawings wherein like reference characters indicatecorrespond- "ing parts throughout the same:

Figure 1 is'a side elevation of a double pulleyembodying my improved safety device.

Figure '2 is an end elevation thereof.

Figure Sis an enlarged vertical sectional View through the pulley block showingthe mounting for the pulleys or sheaves.

' Figure 4 is a vertical sectional view taken approximately on the line 4-4 of Figure 3' showing the. position of the pulley wheel wh'enthe platformjis properly suspended by the cable trainedover the pulley wheel. u

as also clearly illustrated in Figure 3.

Figure '5 is a similar'section showing the broken cable, and

manner in which the tooth bites'into the Figure 6 is a sectional view through the pulley block showing the'tooth in bottom plan. g I V I In the drawings wherein for the purpose of illustrationis shown the preferred embodiment of my invention, the numeral 1 designates a pulley block which in the present in. stance is formed with a pair of pulleys or sheave receiving openings 2 and '3, respectiyely, so that adouble 'pu'lley will be provlded; It is however, understood-that a single pulley may be. employed if so desired.

A suspension eye 4- is' provided atthe top of the pulley block 1. Formed at the top of eachofthe openings 2 and Sand projecting downwardly therefrom is the cable engaging tooth 5 that forms a salient part of the pres ent invention, and the purpose thereof will be presently described indetail.

The-end portions of the pulley blockare cut out as is also thedividing partition 6 arranged between the openings 2 and 3, and this arrangement is more clearly disclosed in Figure 3 of the drawings.

A pair of plates .Tand 8 are arranged in spaced relationwithin each of the cut out portions formed in the ends and intermediate portion-of the pulleyblocks and each of said plates is providedwith a central longitudinally extending slot 9. All of these slots are disposed in communication with each other slotted plates th'atare associated with the intermediate portion 6 of the-pulley block are denoted by the reference characters 10 and 11. "1

- A'pair of horizontally disposed pins 12 and 13, respectively are arranged for vertical slidable movement within the openings 2 and 3, respectively, and'upo'n referring to 'Figure 3, it will be noted-that the pin 12 projects through the slotted plates attheo left hand side of the block 1, and the inner end of this pin extends intokthe openings formed in the intermediate portion 6 that is disposed through the slot formed in the plate 10. The other pin 13 extends through the The t other pair of apertured plates? and 8, and

formed in the intermediate partition '6.

A sheave or pulleywheel 14; is mounted for rotation on the intermediate portion of the pin 12 andisarranged within theopening 2, a similar sheave l5 be-ing supported on the i "intermediateportion of the otherpin 13 for man to safely leave the' scaf'fold oi permit disposition Within the opening 3. The scafhiin'to repair the broken cable.

fold supporting cables are trained over the respective pulleys or sheaves asindicated by the dotted lines in Figure}, and also in Figures 3 and4, the free ends of the cables being attached to the scaffolds or platform in the usual manner. 7 V

The invention further are arranged withinitheopeningsformed in the ends of the intermediate portion ofthe V pulley block 1 andone of such rods is located within each of the end openings for disposition between the spaced plates 7 and 8, while two-of theserods are positioned betweenthe plates 10 and 11. The upper ends of these rods extendthrough the respective ends of" the respective shafts and areformed'at their ley block.

An expansible coil spring 19- encircles the intermediate'portion of each rod .and is dis posed between the bottom of the respective opening in the pulley block, .andthe respective ends of said shaft for normally urging the shaft and the pulley wheels supported thereon in an upward direction.

Additionalcoil springs 20 are provided for effecting the upward movement. of the pulley supporting shaft. These coil springs '20 are connected at their lower ends to the respective heads 17, while the upper ends of the springs 20 are secured to the eyed lower ends of suitable pins 22 that projectupwardly into the top portion of the pulley 7 block 1 as clearly indicated in Figure 3. The

lower'coil springs 19 are expansible to exert an upward sliding movement of the shaft in the slots 9 while the upper coil springs are retractile springs to assist in moving the shaft and the sheaves supportedthereon in an upward direction. I .7

The weight of the scaffold or platform supported by the cables A'exerts a pressure on the shafts to move the same downwardly in the respective slots.9, and the tooth 5 in V comprehends "the 'provisionof ve'rtically disposed rods 16 that However, should either ofthe cables accidentally break, the springs 19 and 20 will automatically move the shaft 12 or the shaft 13 depending upon which of the cables has been broken upwardly, so that the broken cable willbe forced againstthe tooth 5 and this tooth will cooperate withthe sheave and the springs to support the scafiold or platform in such a manner as to enable the work- 7 As heretofore mentioned, this safety device maybe used with a single pulley as well as with a, multiple pulley structure, and the safety mechanism will at all times be positive and efficient as well as automatic in its operation. 7 7

Furthermore, the parts of the safety inechanism are so arranged as not to interfere with the ordinary. use of the pulley, and the parts are so assembled as to enableready access thereto whenever necessary.

WVhile I have shown the preferred embodiment of my invention itis to be understood that, minor changes in the size, shape-and arrangement of-parts may be resorted to without departing from thespirit of the inventionand the scope of the appended claims.

, Having thus described the invention, what I claim as new. and desire to secure by Letters Patent is,:- v

1. In combination witha pulleybloek, a sheave yieldingly mounted therein, automatic means fornormally urgingthe sheave upwardly in the pulley block, said means being disposed in an inoperative position when a downward pull is exerted on a cable trained over the sheave, and means for gripping the cable'when the same accidentally breaksv as in the manner described.

2. In combinationwith a pulley block, a sheave, yieldingly mounted therein, automatic means for normally urgingthe sheave upwardly in the pulley block, said means be 111g disposed in an inoperative position when extending through the opening, the opposite sides of the pulleyv block being formed with slots to accommodate the ends ofthe shaft and inwhich said shaft is arranged for vertical slidable movement, a sheave supported for rotation in the intermediate portion of I the shaft for disposition within the opening in the pulley block, a cable gripping tooth each of the cut out portions 2 and 3 willbe disposed out of engagement with its respective cables.

extending downwardly from the-top of the opening and normally maintained out of sheave, said cable normally exertinga dowin extending through the -opening,the opposite sides of the pulley block being formed with slots to accommodate the ends of the shaft and'in which said shaft is arranged for vertical vslidable movement, a sheave supported for rotation in the intermediate portion of the'shaft for disposition within the opening in the pulley block, a cable gripping tooth extending downwardly from the top of the opening and normally maintained out of engagement with the cable trained over the sheave, said cable normally exerting a downward pressure on the shaftto hold the same in its lowered position in the opening, and spring means associated with the ends of the shaft for automatically moving the shaft and sheave upwardly when the cable is broken to effect the biting engagement of the tooth with the broken cable in the manner as described, said spring means including retractilecoil springs connected at their lower ends to the respective ends of the shaft, the upper ends of the springs being secured. to the upper portion ofthe pulley block on opposite sides of the central opening.

5. In combination, a pulley block formed with a central opening, a transverse shaft extending through the opening, the opposite sides of the pulley block being formed with slots to accommodate the ends of the shaft and in which said shaft is arranged for Vertical slidable movement, a sheave supported for rotation in the intermediate portion of the shaft for disposition within the opening in the pulley block, a cable gripping tooth extending downwardly from the top of the opening and normally maintained outof engagement with the cable trained over the sheave, said cable normally exerting a downward pressure on the shaft to hold the same in its lowered position in the opening, and

spring means associated with the ends of the,

shaft for automatically moving the shaft and sheave upwardly when the cable is broken to effect the biting engagement of the tooth with the broken cable in the manner as described, said spring means comprising vertically disposed sliding pins or rods arranged in the side portions of the pulley block, the upper ends of the rods beingconnecte'd to the respective ends of the shaft, the lower ends of the rods being operable within sockets formed in the bottom portion of the pulley block, and expansible coil springs encircling the rods for disposition between the sockets and the respective ends of'the shaft.

6. In combination, a pulley block formed with a central opening, ,a transverse shaft extendingthrough the opening, the opposite sides of the pulley block being formed with slots'to accommodate the ends of the shaft and in which saidshaft is arranged for vertical slidable movement, a sheave supported for rotation in the intermediate portion of the shaft for disposition within the opening in the pulley block, a'cable gripping tooth extending downwardly from the top of the opening and normally maintained out of engagement with the cable trained over the sheave, said cable normally exerting a clownward pressure on the shaft to hold the same in its lowered position in the opening, and

spring means associated with the ends of the shaft for automatically moving the shaft and sheave upwardly when the cable is broken to effect the biting engagement of the tooth with the broken cable in the manner as described, said spring means comprising vertically disposed sliding pins or rods arranged in the side portions of the pulley block, the upper ends of the rods being connected to the respective ends of the shaft, the lower ends of the rods being operable within sockets formed in the bottom portion of the pulley block,

expansible coil springs encircling the rods for I disposition between the sockets and the respective ends of the shaft, the upper ends of the rods projectingthrough the respective ends of the shaft, and retractile coil springs connected at their lower ends tothe upper projecting ends of the respective'rods and at their upper ends to the top portion of the pulley block. I

In testimony whereof I affix my signature.

CHARLES DUBUQUE. 

